Hard disk drives are used in almost all computer system operations. In fact, most computing systems are not operational without some type of hard disk drive to store the most basic computing information such as the boot operation, the operating system, the applications, and the like. In general, the hard disk drive is a device which may or may not be removable, but without which the computing system will generally not operate.
The basic hard disk drive model includes a storage disk or hard disk that spins at a designed rotational speed. An actuator arm is utilized to reach out over the disk. The arm carries a head assembly that has a magnetic read/write transducer or head for reading/writing information to or from a location on the disk. The transducer is attached to a slider, such as an air-bearing slider, which is supported adjacent to the data surface of the disk by a cushion of air generated by the rotating disk. The transducer can also be attached to a contact-recording type slider. In either case, the slider is connected to the actuator arm by means of a suspension. The complete head assembly, e.g., the suspension and head, is called a head gimbal assembly (HGA).
In operation, the hard disk is rotated at a set speed via a spindle motor assembly having a central drive hub. Additionally, there are tracks evenly spaced at known intervals across the disk. When a request for a read of a specific portion or track is received, the hard disk aligns the head, via the arm, over the specific track location and the head reads the information from the disk. In the same manner, when a request for a write of a specific portion or track is received, the hard disk aligns the head, via the arm, over the specific track location and the head writes the information to the disk.
Over the years, the disk and the head have undergone great reductions in their size. Much of the refinement has been driven by consumer demand for smaller and more portable hard drives such as those used in personal digital assistants (PDAs), MP3 players, and the like. For example, the original hard disk drive had a disk diameter of 24 inches. Modern hard disk drives are much smaller and include disk diameters of less than 2.5 inches (micro drives are significantly smaller than that). Advances in magnetic recording are also primary reasons for the reduction in size.
This continual reduction in size has placed steadily increasing demands on the technology used in extracting particulate from the hard disk drive and the components thereof. For example, particulate contamination has been one of the major contaminations encountered in HDD (Hard Disk Drive) industries, on its components, in its assembly processes.
Presently, as shown in background FIG. 1a, US/LPC (Ultrasonic Extraction/Liquid Particle Count) is a well established LPC method for extracting particulates from components of a HDD. Moreover, US/LPC has been widely used in HDD industries for many years.
In general, the US/LPC 100 method includes providing a tank 120 with a liquid 125 therein. A container 105, filled with an amount of extracting liquid 115 and the component 110, is placed into the tank 120. Ultrasonic energy is then provided to the liquid 125 in tank 120. The ultrasonic energy transfers through the liquid 125 and into the extracting liquid 115 in container 105. The component 110 is ultrasonically extracted and the extracting liquid 115 receives the removed particles. The particle filled liquid 115 is then taken for LPC. The particle sized detected can be 2 um, 0.5 um, 0.3 um or 0.2 um, or smaller; and the Ultrasonic Frequency commonly used can be one of the following: 40, 68, 80, 120, 132, 140, 170, 192, 220, 270 kHz, or even high frequencies.
However, the ultrasonic extraction method is extremely stressful on the component 110 during the extraction process. That is, the number of particles that are found after extracting, via the LPC, is high and is mainly due to the ultrasonic energy eroding connected base material, rather than removing loose particles, from the component 110.
For example, FIG. 1b provides a graph of particles found after ultrasonically extracting a component 160 without a scratch and an equivalent component 170 with 4 lines of scratches. From the graph 150, it is apparent that there is no significant deviation between the two components 160 and 170. In other words, the component 160 with no scratches provides a statistically similar number of particles as the component 170 with four lines of scratches.
Therefore, what is needed is a gentle extraction method for utilization on HDD components, subassemblies, whole drive, tools/jigs, HDD consumables, and any other non HDD items which require particle extracting.